Refinement of technique in the martial arts is classically done by practicing under the observation of a qualified instructor. The student watches a demonstration or listens to an explanation and then does his best to match his own performance to that of the instructor. The instructor watches the student closely and offers suggestions on how to improve.
One on one instructor is the ideal situation for learning, but often, the student is only one of many in a class. He practices his moves, perhaps interacting with fellow students until the instructor has time for him. There are, perhaps, other approaches which can be used in addition to personal instruction. One of these is Realtime Visualization.
Visualization is a proven training aid for atheletes. The student strives to create a mental movie in which he performs technique in response to moves on the part of an imagined opponent. The internal image should be as rich and as detailed as possible, down to the actual feelings in his joints, the force and contact used, etc. The internal movie can be varied for different situations, changes in the dynamics, and other parameters. Phil Porter once told me that he considered visualization to be an important part of his training Judo players for the Olympics.
Normally, visualization is considered a kind of meditation. The scripts are run internally, visualized without actual movement. Suppose that the student actually performed his moves in response to an internally visualized script? This is what I call Realtime Visualization. Many techiques in Aikido, both body and weapon training are pre-determined in their outcomes, ie., it is scripted advance. Kumi-tachi forms are an example of this kind of training.
Realtime Visualization would call for the student visualizing how he should perform a technique or move while simultaneously executing it. What is the point, you may ask? This approach offers the student realtime feedback on the difference between his expectations of how a technique should be done, versus how it is actually being done. It allows the student to focus in on very fine details which normally would escape notice. Am I breathing correctly? Is my hand holding the weapon properly. Am I extending the sword fully at this point? Did contact come at the right time. Etc, etc.
Naturally, the tanto is completely different in weight, feel, and balance than a bokken. However, I had the students attempt to visualize that they were actually holding a real bokken. Create a mental image of lifting the sword to jodan no kamae and cutting shomenuchi. The hands feel contact with a wooden object, but the mind must supply the actual balance and feel of the bokken. After a time, the students started to cut with the tanto as if they were using a bokken.
Next, I had each student perform the same suburi forms with a suburito. The suburito is a very heavy sword, longer and thicker than a regular bokken. The contrast with the tanto was striking. Several of the students had trouble controlling the suburito, trying to cut with it as if it were a regular bokken, but unable to detach themselves from its greater mass. Now the attempt was to visualize a lighter weapon and perform the suburi correctly.
In both cases, the mental image of how to cut and perform the suburi forms was quite familiar to the students. Holding a weapon which different greatly from what they were used to allowed them to compare and contrast their actual performance verses the mental movie. Done with the proper mindset, this exercise reveals the strengths and weaknesses of their skill with the bokken.